Study On Luminescence Tuning And Application Of Mn/In-doped All-inorganic Halide Perovskite Materials

Lead halide perovskite has broad application prospects in optoelectronic devices because of its superior optical and photoelectric properties.However,the lead toxicity and environmental instability of lead halide perovskite hinder its application.In view of the containing lead element and its poor stability,lead-free halide perovskite materials with good stability are explored and synthesized,and the luminescence properties of halide perovskite materials can be tuned through doping metal ion,so as to further expand the application of halide perovskite.The specific research contents are as follows:(1)Herein,Mn²⁺-doped CsCdCl₃ perovskite long afterglow single crystals with tunable afterglow time,improved efficiency and stability,were synthesized by hydrothermal method.By controlling the concentration of the doped Mn²⁺ions(0-15%)in the CsCdCl₃ perovskite,the distribution and concentration of traps can be effectively adjusted,resulting in the increase of afterglow time from 5 min to 24 min.The characteristic emission of d-d transition of Mn²⁺is realized,and the photoluminescence quantum yield(PLQY)is up to 91.4%.The stability test shows that these materials are very stable to humidity and temperature.When the temperature reaches 150°C(423 K),the PL integral intensities of all samples are greater than 90%.The PL intensity retained more than 75%of initial value after immersion in water for 55 days.These excellent properties show the application prospect of the afterglow material in lighting indication and anti-counterfeiting.(2)The tuning effect of Mn²⁺-doped CsCdCl₃ perovskite on its emission properties was studied.By changing the doping concentration of Mn²⁺ions,the emission peak position was tuned from 596 nm to 632 nm,gradually changed from orange to red,and the half peak width gradually increased from 71 nm to 95 nm.The influence of Mn-Mn pairs coupling on the emission spectrum is confirmed by Electron paramagnetic resonance(EPR)and fluorescence decay life analysis.The formation of Mn²⁺pair leads to the red shift of spectrum and the increase of half peak width.The samples were placed in the air environment for a long time,and the analysis results showed that the structure and performance stability of the samples are good.The samples CsCdCl₃:20%Mn and CsCdCl₃:50%were applied to LED devices respectively obtained warm white LED.The color rendering index of the former is Ra=81 and the color gamut value is 84.7%NTSC.The latter has better performance,the color rendering index is Ra=84,and the color gamut value reaches 90.1%NTSC.It shows that the luminescence tuning of Mn²⁺ions is effective in practical application.(3)The tunable visible light emission characteristics of doped In³⁺ions in direct band gap lead-free double perovskite Cs₄Mn Bi₂Cl₁₂ were studied.The Bi³⁺ion is replaced by the smaller In³⁺ion causing distortion of the[Mn Cl₆]^4-octahedron,which changes the local crystal field strength of the Mn²⁺ion,and makes the emission band centered at 606nm gradually red-shifts to 616 nm.By employing Cs₄Mn Bi₂Cl₁₂ and Cs₄Mn(Bi_0.88In_0.12)₂Cl₁₂ as red-emitting phosphors,LED-1 with Ra=82 and CC=4510 K and LED-2 with Ra=86 and CCT=4280 K were obtained,respectively.Compared with Cs₄Mn Bi₂Cl₁₂,Cs₄Mn(Bi_0.88In_0.12)₂Cl₁₂ contributes a wider color gamut in LED devices.As the red saturation display index R9 increases from 65 to 72,the color gamut value increases from 74%to 76.4%NTSC.The current work provides a new direction for the regulation of optoelectronic properties in layered double perovskite...